Catheter system for performing intramyocardiac therapeutic treatment

ABSTRACT

The multilumen catheter ( 2 ) is provided at one end with a needle system ( 9, 9 ′) formed by two or more single-lumen needles which are provided with respective discharge openings ( 110, 111 ) and which, via their longitudinal lumina ( 10, 11 ), are connected to corresponding lumina ( 3, 4 ) of the catheter for separate release of a tracer fluid for external image diagnostics systems and therapeutic fluids, for example DNA plasmids. The needles may be both straight or both helical or one of these needles may be straight and the other needle may be helical.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a divisional or of application Ser. No.09/831,493, which is the National Stage of International Application No.PCT/ep99/08686, filed Nov. 11, 1999.

BACKGROUND OF THE INVENTION

[0002] The invention relates to a method and the associated apparatusfor performing intramyocardiac therapeutic treatment by means of thecontrolled infusion, in this anatomical location, of therapeutic fluidsof varying nature and composition. With this method and apparatus it ispossible to treat patients who suffer from cardiac ischaemia and who arenot able to tolerate surgical therapy involving a coronary bypass orcoronary angioplasty using catheters. At present there are many patientssuffering from heart disease which is advanced to the point where it canno longer be treated using the solutions mentioned. Completere-vascularization is not possible in 20% of the patients who undergobypass surgery. The patients who cannot be treated with theabovementioned solutions belong, for example, to the followingcategories: patients with extensive heart disease affecting the distalvessels; patients with symptomatic ischaemia resulting from a diseasedvessel which is too small to be bypassed; patients who do not haveadequate ducts for bypassing; patients with total chronic occlusion andwith distal vessels which are small and/or cannot be viewed.

[0003] A new therapy which is currently becoming more widespread for thetreatment of this type of patient consists in the percutaneousinjection, into the cardiac muscle, of genic substances, for example DNAplasmids, which induce the formation of new blood vessels. At least sixdifferent carrier systems have been used for genic transfer to the heartmuscle cells, namely: DNA devoid of viral or physical adjuvants whichincrease the genic release; DNA encapsulated in modified liposomes; DNAcomplexed with cationic liposomes; retroviral carriers; adeno-associatedviral carriers. This therapy is currently performed by making a smallincision in the chest in order to inject the abovementioned plasmidsinto the myocardium, continuously monitoring the patient by means oftransoesophageal echocardiography in order to check the movement of thecardiac wall during the percutaneous injection, in order to prevent theplasmid being injected into the blood, inside the cavity of theleft-hand ventricle. The recent clinical experiments involving injectionof plasmids into the myocardium, during surgical treatment or amini-thoracotomy, are very interesting, but are unable to solve manyproblems when this procedure is used as the one and only therapy, inparticular problems relating to optimization of the most suitable sitefor injection and the number and dosing of the intramyocardialinjections. It is also obvious that the surgical solution limits verymuch the possibility of performing multiple treatment or treatment whichis repeated over time.

[0004] It was thought that a catheter system suitable for theintramyocardiac injection of plasmids may be able to overcome thelimitations of the present surgical solution indicated above.

[0005] According to the publication “Percutaneous Transluminal GeneTransfer into Canine Myocardium in Vivo by Replication-DefectiveAdenovirus” Jian Jun Li et. al. (Cardiovascular Research 1995; 30:97-105), previous experiments involving the percutaneous injection ofgenes into the myocardium of dogs, by means of adenovirus, wereperformed using an injection catheter composed of a catheter guide and aguided catheter, with a needle at its terminal end, inserted into theleft-hand ventricle of the heart. Under a fluoroscope, the needle wasinserted into the myocardium and its correct position of insertion wasconfirmed by suction of the blood. If the needle is inserted into thewall of the cardiac muscle, its lumen is closed by the muscle itself andtherefore the suction of blood is prevented.

[0006] Various injection catheters have been studied in order to improvethe injection of a drug into an area inside the human body. Injectioncatheters have for example been produced by Wilson Cook Medical Inc.(Cook Italia Srl), said catheters being specifically designed for thesclerotherapeutic endoscopic treatment of oesophageal varices. TheBoston Scientific Corporation markets needles for liquid injectiontherapy using a dedicated twin-lumen catheter and associated extendableand retractable needle with an ample washing lumen for ensuring visionwith an endoscope in bleeding conditions.

[0007] None of the catheters with injection needles proposed by thecurrent technology has been specifically developed and can neither beadapted to solve the problem of percutaneous and transvascular injectionof plasmids into the human myocardium. With a needle catheter of theknown type it is difficult to maintain a fixed position inside themoving wall of the myocardium and it is therefore difficult to inject,in a reliable manner, plasmids into the said wall. Similar difficultieshave been encountered with the catheters of pacemakers when they have tobe positioned in a different point of the apex of the right-handventricle, for example in the interatrial or interventricular septum. Inthese cases, a helical electrode screwed into the wall of theendocardium, in order to ensure immediate stability of the implantpending the growth of tissue thereon, is used. The use of a helical andhollow electrode for the injection of liquids into the human body hasbeen described in U.S. Pat. No. 5,431,649 for a purpose different fromthat of the present invention, namely for the hyperthermic treatment ofneoplasia of the prostate and for treatment of myocardiac ablation bymeans of radiofrequency, using a perfusion of saline solution throughthe cavity of the helical electrode.

[0008] An important factor which prevents the use of the abovementionedcatheter perfusion systems for the function in question is the fact thatthey are not able to provide a safe, reproducible and recordable methodfor demonstrating that the injection of the plasmids is performed in aselected area of the myocardium and not in the blood stream; in fact theaforementioned solution of confirming the position of the needle bysuction is not suitable for this purpose on account of the high risk offalse situations created by the closure of the needle lumen by bloodclots.

[0009] A recent publication “Transcatheter Subendocardial Infusion. ANovel Technique for Mapping and Ablation of Ventricular Myocardium”,Andreas Goette et. al. (Circulation 1996; 94: 1149-1455) described aninfusion catheter equipped with an electrode corresponding to theinjection needle located on the distal end of said catheter and providedwith a second ring electrode in the vicinity of the same needle. Twolumina which are formed inside the catheter and by means of which it ispossible to perform a sequential administration of fluid mixturesconverge towards this needle. A tracer substance is injected via a lumenof the catheter in order to map, by means of fluoroscopy, the point ofinjection of the needle into the myocardium of the left-hand ventricle,while a fluid mixture with ethanol is subsequently injected through thesecond lumen of the catheter in order to perform a chemical ablation ofa volume of the myocardium. By means of this method, with the associatedcatheter, it is possible to identify with reasonable certainty the areaof the myocardium into which the needle is inserted, but the problems,as described in the abovementioned publication, resulting from thedifficulty of keeping a straight needle in the correct position in abeating myocardium and preventing remixing between the fluids introducedthrough the two catheter lumina, the latter intercommunicating via thecommon lumen of the injection needle, cannot be solved. Owing to theinherent elasticity of the material from which the lumina of thecatheter may be made and the notable curvature to which the catheteritself is subject during insertion into the human body, it cannot beruled out that the pressure exerted on a fluid which is to be injectedmay cause a partial transfer of this fluid from its lumen under pressureto the other lumen which is at a lower pressure, with the result ofunexpected and constant mixing of the two fluids and possible limitationof the volume of,the fluid actually injected into the myocardium, sincea part of this fluid, instead of being discharged from the needle, flowsback into the lumen of the catheter which is at a pressure less thanthat of the active lumen.

[0010] U.S. Pat. No. 5,354,279 (“Plural Needle Injection Catheter”)envisages a catheter provided at its terminal end with a plurality ofthin pre-formed metal needles emerging in a ray-like arrangement anddesigned to release pharmaceutical substances onto the arteries. Thelumina of these needles communicate, however, with a single lumen of thecatheter so that this apparatus may not be used for the purposes of thepresent invention, either.

[0011] Document U.S. Pat. No. 5,322,510 A (Lindner et al), whichconstitutes the closest prior art, discloses a catheter system forperforming a therapeutic treatment, comprising

[0012] a hollow catheter body provided on its terminal end with a needlesystem for the injection of fluids through the said catheter,

[0013] said body of the catheter having at least two longitudinal luminawhich are connected at one end to external means for administeringfluids,

[0014] the needle system having at least two longitudinal luminaconnected to the corresponding lumina of the catheter.

[0015] By way of conclusion, the known art, with the procedures and thedevices described based on a catheter system with injection needle, doesnot allow the practical realization of an apparatus and a method forinjecting plasmids solely using the intramyocardiac method, owing toproblems associated with the movement of the endocardium and theimpossibility of separating completely injection of the therapeuticfluids from injection of the tracer fluid.

SUMMARY OF THE INVENTION

[0016] The object of the invention is to solve these and other problemsof the already known art by means of a catheter provided with two ormore longitudinal lumina and provided at its terminal end with amultilumen needle system, each lumen of this needle system having itsown discharge opening and being connected to a corresponding lumen ofthe catheter. The lumina of the catheter are connected to externalsystems for releasing separately tracer fluids for external imagediagnostics systems by means of which it is possible to verify thecorrect position of the needle in the cardium tissue and releasetherapeutic fluids, for example DNA plasmids. The needle system inquestion may be formed by a multilumen needle or by several single-lumenneedles arranged alongside each other and each connected to acorresponding lumen of the catheter.

[0017] More particularly, the present invention relates to a cathetersystem of the type as disclosed above with reference to the citeddocument U.S. Pat. No. 5,322,510 A, further characterised by the factthat the said longitudinal lumina are provided with respective lateraldischarge openings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further characteristic features and advantages arising therefromwill appear more clearly from the following description of certainpreferred embodiments thereof, illustrated purely by way of anon-limiting example in the accompanying sheets of drawings, in which:

[0019]FIG. 1 is an overall side view, with parts shown in cross section,of the catheter system according to a preferred embodiment of theinvention;

[0020]FIG. 2 shows a cross section through the middle of the catheter,along the line II-II of FIG. 1;

[0021]FIGS. 3 and 4 show further details of the end part of the catheterwith a multilumen needle, which is sectioned respectively along thelines III-III and IV-IV of FIG. 2 and with parts being visible;

[0022]FIG. 3a is a variation of embodiment of the straight needle;

[0023]FIGS. 5 and 6 are cross sections through the multilumen needlealong the lines V-V and VI-VI of FIG. 3, respectively;

[0024]FIG. 7 shows, longitudinally sectioned, the end part of amultilumen catheter, with the multilumen needle system being formed bytwo single-lumen and straight needles arranged alongside each other;

[0025]FIGS. 8 and 9 show possible cross sections through the needles ofthe needle system according to FIG. 7, sectioned along the lineVIII-VIII;

[0026]FIG. 10 shows, cross sectioned and with parts visible, a needlesystem formed by two straight and coaxial needles;

[0027]FIGS. 11 and 12 show details of the needle system according toFIG. 10, sectioned along the lines XI-XI and XII-XII, respectively;

[0028]FIG. 13 shows, cross sectioned and with parts visible, a needlesystem formed by two helical needles arranged alongside each other;

[0029]FIG. 14 shows, cross sectioned and with parts visible, a needlesystem formed by two straight needles coaxial with each other and ofdifferent length and with the projecting needle portion having a helicalshape;

[0030]FIGS. 15 and 16 show, cross sectioned and with parts visible,further needle systems formed by a straight axial needle circumscribedby a helical needle which may be, respectively, projecting or retractedwith respect to the said axial needle.

DETAILED DESCRIPTION OF THE INVENTION

[0031] In FIGS. 1 and 2 the numeral 1 designates schematically acatheter guide of the known type which is pre-formed or steerable andwhich is inserted into the blood circulation which leads to the leftventricle of the heart and inside which the catheter system in questionis then inserted, said catheter system comprising a catheter 2 which hasa suitable length and cross section and is made of any material suitablefor this purpose, for example Polyimide, and is provided internally witha meshwork braiding 102 and/or other suitable means (see also FIG. 3)which allow a twisting torque to be applied to the said catheter,without the latter being deformed, such that a rotation applied to thefront end of the catheter results in an identical rotation of theterminal end of this catheter. The catheter 2 is provided internallywith several longitudinal lumina, for example a pair of main andopposite lumina 3 and 4, for example having a cross section in the formof a circle segment, and has between said lumina, in a symmetricalarrangement, arranged alongside each other and aligned along thediametral plane of the catheter, three secondary lumina 5, 6 and 7, forexample with a round cross section, one of which is located preferablycoaxially in the catheter, for receiving the guide spindle 8 which is ofthe type usually used for operating traditional pacing catheters.

[0032] A multilumen needle system is fixed onto the terminal end of thecatheter 2 by means of a special insert 12, in a position oflongitudinal alignment with the said catheter, said needle system beingformed by a needle which may be straight as indicated by 9′ in FIG. 3aor may preferably have a cylindrical helical shape, as indicated forexample by 9 in FIGS. 3 and 4. It is understood that the scope of theinvention also includes helical needles other than that illustrated, forexample which are of the straight type and have one or more externalhelices, for example similar to wood screws. From FIG. 5 it can be seenthat the needle has two longitudinal lumina 10 and 11 which are arrangedclosely alongside each other and divided by a common wall 309 over thewhole length of the body of this needle. The base of the needle has afork-shaped configuration and the corresponding branches 109 and 209,which form a continuation of the respective lumina 10 and 11 of the saidneedle, are engaged in the corresponding lumina 3 and 4 of the catheter.

[0033] Both in the case of FIG. 3 and in the case of FIG. 3a, theinternal lumina of the needle are provided with respective lateraldischarge openings, one of which is indicated by 110 and is located at ashort distance from the needle tip, while the other one indicated by 111is located further upstream, in the middle part or at the base of thesaid needle (see also FIG. 6).

[0034] The terminal end of the catheter is provided with a retractabledevice, which is useful as an end-of-travel stop, for stoppingpenetration of the needle 9 or 9′ into the wall of the myocardium whichhas to be treated. For this purpose it may be possible to use atorus-shaped balloon 13 which is made of impermeable and flexiblematerial and which is fixed laterally onto the terminal end of thecatheter 2 and has at least one internal duct 113 which passes throughthe insert 12 and is designed to engage into one of the secondary luminaof the catheter, for example into the lumen 6 (FIG. 2).

[0035] From FIG. 4 it can be seen that the end of an electricalconductor 14 which runs along the whole length of the catheter and ishoused inside one of the secondary lumina, for example the lumen 7 inFIG. 2, is connected to the body of the needle 9 or 9′, together with anoptional additional electrical conductor 15 connected to an optionalring 16 which is made of electrically conducting material and is fixedon the outside of the terminal end of the catheter and is useful as areference electrode for the various operations where the needle acts asa conductor of electrical impulses. The conductors 14 and 15 aresuitably insulated from each other. If the braiding 102 of the catheteris made of an electrically conducting material, it may replace eitherone of the said electrical conductors 14 or 15. It is understood thatthe function of reference electrode may be performed by means other thanthe ring 16 mentioned above, for example using solutions known in thesector of cardiac electro-stimulation.

[0036] From FIG. 1 it can be seen that the initial section of thecatheter passes through the body of a distributor 17 with respect towhich the said catheter may rotate, but not move axially, for exampleowing to the presence of end stops 18 and 19. The knob 20 by means ofwhich a rotation may be imparted to the said catheter is fixed onto thefront end of the catheter, whereas, with regard to that stated above,the distributor 17 may remain at a standstill. The front ends of theelectrical conductors 14 and 15 are connected to small electricallyconducting rings 21 and 22 which are fixed externally to differentpoints of the catheter body, are insulated with respect to each otherand with which brushes 23 and 24 of the distributor 17 co-operate, saidbrushes being in turn connected via respective conductors to acomposite, external, fixed apparatus 25, which will be described ingreater detail below.

[0037] The lumina 3, 4 and 6 of the catheter are closed at the outerfront end and are provided along the section which passes through thedistributor 17 with respective radial openings which are situated atmutually distant points of the catheter and lead into respective annularchambers 26, 27 and 28 of said distributor and which are insulated fromeach other and from the exterior by annular sealing gaskets 29, 30, 31and 32. These chambers lead to cable connectors 33, 34 and 35 to whichflexible pipes 36, 37, 38 may be connected, said flexible pipes beingprovided at the other end with Luer connectors to which syringes 39, 40,41 may be connected, the first thereof being useful, for example, forinjecting or drawing liquid into/from the balloon 13, i.e. for fillingit and activating it as shown in FIG. 4 or for reducing it into thecollapsed condition as shown in FIG. 3, while the syringe 40 is usefulfor example for injecting tracer liquid which will emerge, for example,from the opening 111 of the needle 9 or 9′, and the syringe 41 is used,for example, for injecting DNA plasmids which for example will bedischarged from the end opening 110 of the said needle.

[0038] The catheter system as described functions and is used in thefollowing manner. After positioning the catheter guide 1 in the patient,the catheter 2 is inserted inside said guide by means of the specialguide spindle 8. The end balloon 13 is in the collapsed condition. Afterinsertion of the catheter, the balloon 13 is activated by means of thesyringe 39 and, by means of the external knob 20, the catheter itself isrotated in the direction for screwing of the helical needle 9 into themyocardium, until this needle has been completely screwed in. Thecorrect position of the needle may be verified from the outside by meansof the apparatus 25 which detects, for example, a bioelectricalimpedance and/or ECG, using the electrical conductor 14 connected to theneedle and the conductor 15 connected to the annular reference electrode16. In order to improve the results of this test, the needle 9 or 9′ maybe advantageously lined with a thin layer of electrically insulatingmaterial, for example, Parylene, over practically the whole length, asschematically indicated by the broken lines and by 45 in FIGS. 3a and 4,except for an appropriate tip portion which remains electricallyconducting.

[0039] Once screwing of the needle into the myocardium has beenperformed, via the syringe 40, a correct quantity of tracer is injectedinto this wall and, if the needle is correctly inserted, remains for arelatively long period of time in the said wall and may be easilydetected by external image diagnostics systems of the known type, in theform of a persistent spherical-shaped mark. Should the needle not becorrectly inserted into the myocardium, the injected tracer would becomedispersed in the blood stream. The injected tracer may for example be ofthe type which is useful for detection by means of X-rays or usingultrasound image or magnetic nuclear resonance systems. If a dual-lumenneedle as shown in FIGS. 3 and 3a is used, the tracer fluid ispreferably discharged from the orifice 111 of the needle itself since,if it is subsequently established using the abovementioned procedurethat the needle is correctly inserted in the myocardium, there is theabsolute certainty that the other discharge orifice 110, intended forthe discharge of therapeutic fluid, is also correctly inserted into themyocardium itself.

[0040] After verifying and documenting with appropriate means that theneedle has been correctly inserted, DNA plasmids are injected into themyocardium via the syringe 41. In order to reinforce the transfer of theabovementioned plasmids into the cells of the cardiac tissue, theexternal apparatus 25 may be arranged so as to transmit into the tissueitself, via the electrical circuit connected to the needle 9, electricalimpulses which have suitable characteristics and are synchronized withthe beat R of the spontaneous activity of the heart. Again for thispurpose, the external apparatus 25 may be designed to generateultrasounds which are conveyed to the needle 9 and therefore to theperfused zone of the myocardium, via a conductor with suitablecharacteristics, which is indicated schematically in FIG. 1 by 42 andwhich is for example connected to the needle via the axial lumen 5,after removal of the guide spindle 8. It is understood that the cathetermay have a secondary lumen specifically designed to contain anultrasound conductor connected to the needle 9 or 9′.

[0041] With reference to FIGS. 7 to 16, variations of embodiment of theneedle system mounted on the catheter will now be described, saidcatheter, unlike the one previously considered, being composed of twosingle-lumen needles. The catheter 2 illustrated in FIG. 7 is identicalto the multilumen catheter illustrated in FIG. 1 and its lumina 3 and 4,which are respectively connected to the external systems for injectionof the therapeutic fluid and the tracer fluid, are joined to the endsections 109, 209 of respective straight and single-lumen needles 9′aand 9′b which are preferably of different length, preferably arranged inaxial alignment with the catheter and preferably fixed together by meansof welds 43, as can be seen from FIG. 8. 10 and 11 indicate the luminaof the needles which terminate in respective openings 110, 111 fordischarging the fluids conveyed by said lumina. The tip of the shorterneedle is preferably shaped in the manner of a flute mouth-piece and issuitably connected to the side surface of the adjacent needle in orderto facilitate penetration, into the myocardium, of the needle system 9′thus formed. FIG. 9 illustrates a variation according to which theneedles 9′a and 9′b have a flattened—for example semi-circular—crosssection so that the needle system 9′ formed by them can be made toassume a substantially round cross section.

[0042] In the solution according to FIGS. 10, 11 and 12, again relatingto a needle system 9′ of the straight type, the longer needle 9′a ispartly inside and coaxial with the shorter needle 9′b, the end part ofwhich is closed, converging onto the needle 9′a, and may be providedwith several lateral openings 111 for discharging the tracer fluid. Theneedle 9′a emerges in a sealed manner from the needle 9′b at the startof the bifurcation which forms the end sections 109 and 209 forconnection to the lumina 3 and 4 of the catheter.

[0043] The solution according to FIG. 13 is equivalent to that of FIG.7, but envisages a needle system 9 which is formed by two helicalneedles 9 a and 9 b which are arranged alongside each other andpreferably fixed by means of welding and which extend around the axis ofthe catheter 2. The comments made with reference to FIGS. 8 and 9 forthe solution of FIG. 7 are also applicable here. The needles enterpreferably into the catheter being closely arranged around its axis andthen diverge away from each other and engage into the lumina 3, 4 withthe end sections 109, 209. It is understood that the scope of theinvention also includes the variant, not shown, whereby the helicalneedles 9 a and 9 b are staggered and distant from each other, with thetip of the shorter needle being distant from the body of the longerneedle. In this case the needles may enter into the catheter withsections which are distant from the axis of the said catheter.

[0044] The solution according to FIG. 14 is derived from that of FIG. 10and envisages a needle system 9 formed by a short needle 9′b of thestraight type from which a needle 9 a terminating in a helical shapeprojects coaxially.

[0045] The solution according to FIG. 15 illustrates a needle system 9formed by a straight short needle 9′b which is aligned axially with thecatheter and by a long helically shaped needle 9 a which extendsconcentrically around the said central needle 9′b.

[0046] The solution according to FIG. 16 is a variation of the solutionaccording to FIG. 15 and envisages a needle system 9 formed by a longstraight central needle 9′a and by a helically shaped external needle 9b which extends concentrically around the said central needle. Thissolution could be preferred to that of FIG. 15 since the straightcentral needle 9′a is inserted firstly into the myocardium and acts as acentring element and a rotational pivot for the helical needle 9 b. Inboth solutions according to FIGS. 15 and 16, the helical needle is ableto enter into the catheter with an arrangement close to the straightneedle, as illustrated by continuous lines, or is able to enter into thecatheter with an arrangement offset from the axis of the straightcentral needle, as indicated by A and B, in order to favour, ifnecessary, automatic stopping of the screwing action of the needlesystem.

[0047] In FIGS. 7 to 16, 44 denotes in broken lines the location, ifnecessary, on the terminal end, of the catheter, of an ultrasoundgenerator which is integral with the base of one or both needles andconnected to an electrical supply circuit, not shown, which passesthrough a secondary longitudinal lumen of the catheter for connection toan external power supply unit. With this solution it is possible totransmit to the needle system, and therefore to the perfused zone of themyocardium, the ultrasounds which are necessary for reinforcing thetransfer of the therapeutic fluid into the cells of the myocardiumtissue. It is understood that the same comments made in respect of thepreceding solutions are applicable to the variations according to FIGS.7 to 16, with regard to the possibility of electrical connection of theneedle system to external apparatus and partial insulation of the saidneedle system, except for a suitable section of its terminal part, usingelectrical insulation material, for example based on “Parylene”. Thecatheter will also be provided on the terminal end with the electricallyconducting ring 16 having the function of a reference electrode for allthe operations which the needle system performs as a conductor ofelectrical impulses. The catheter will also be provided with theinternal anti-twisting braiding 102 and on the terminal end of the saidcatheter the already mentioned retractable device 13, with externalactivation and deactivation controls, for stopping penetration of theneedle system into the myocardium will be provided.

[0048] It is understood that the dimensions and the proportionsindicated in the drawings are purely exemplary and do not limit thescope of the invention. Purely by way of a non-limiting example, somedimensional characteristics for the construction of the apparatusaccording to the invention are now described. The catheter 2 may, forexample, have an external diameter of about 7 French, that is to sayabout 2.1 mm, while the external diameter of the helix of the needlesystem with at least one helical needle, may for example be about 2 mm.The projecting part of the longer needle must not, for example, exceedthe length of about 5 mm, while the projecting part of the shorterneedle will have for example a length of about 2.5-3 mm. The needleswhich form the needle system may for example each have an externaldiameter of about 0.30 mm.

1. Catheter system for performing intramyocardiac therapeutic treatmentcomprising: a catheter having a hollow catheter body provided on itsterminal end with a needle system for the injection of fluids throughsaid catheter; the body of the catheter having at least two longitudinallumina which are connected at one end to external means foradministering fluids; the needle system having at least two longitudinallumina connected to the corresponding lumina of the catheter; whereinsaid longitudinal lumina are provided with respective lateral dischargeopenings.
 2. Catheter system according to claim 1, in which the terminalend needle system of the catheter consists of a multilumen needle. 3.Catheter system according to claim 1, in which the at least one of saidlongitudinal lumina of the needle system is obtained in a needle ofhelical type.
 4. Catheter system according to claim 2, in which themultilumen needle is of the helical type.
 5. Catheter system accordingto claim 1, in which the terminal end needle system of the catheter isformed by at least two single-lumen needles.
 6. Catheter systemaccording to claim 5, in which the needles which form the needle systemare of different lengths.
 7. Catheter system according to claim 1, inwhich the discharge openings of the lumina of the needle system are indifferent longitudinal positions of the needle itself.
 10. Cathetersystem according to claim 6, in which the shorter needle is providedwith several lateral discharge openings.
 11. Catheter system accordingto claim 5, in which the needle system is formed by two helical needlesof different length which are centered with respect to the axis of thecatheter.
 12. Catheter system according to claim 11, in which thehelical needles are arranged alongside each other and fixed with welds,the tip of the shorter needle being integral with and connected to thebody of the longer needle.
 13. Catheter system according to claim 12, inwhich the helical needles have a cross section which is flattened andsuch that the needle system formed by it has a substantially round crosssection.
 14. Catheter system according to claim 12, in which the helicalneedles enter into the catheter with straight sections arranged alongthe axis of the said catheter.
 16. Catheter system according to claim 1,in which the needle system is formed by a straight needle aligned withthe axis of the catheter and by a helical needle arranged concentricallyaround said central needle.
 17. Catheter system according to claim 16,in which the central straight needle is shorter than the helical needle.18. Catheter system according to claim 16, in which the central straightneedle is longer than the helical needle so as to act as a centeringdevice and rotational pivot for said helical needle.
 19. Catheter systemaccording to claim 16, in which the helical needle enters into thecatheter with a section located alongside the central needle. 20.Catheter system according to claim 16, in which the helical needleenters into the catheter with a section distant from the central needleso as to prevent the rotation of the catheter when this section comesinto contact with the wall of the myocardium.
 22. Catheter systemaccording to claim 1, in which the needle system is electricallyconducting.
 23. Catheter system according to claim 22, in which theelectrically conducting needle system is lined with a thin film ofelectrically insulating material over nearly the whole of its length,except for a suitable tip section which remains electrically conducting.24. Catheter system according to claim 23, in which the electricallyinsulating material which partly lines the needle system comprisesmaterial known as “Parylene”.
 25. Catheter system according to claim 22,in which the body of the catheter comprises a first longitudinalelectrical conductor connected at one end to the needle system anddesigned for connection at the external end to an external electricalapparatus.
 26. Catheter system according to claim 1, characterized inthat the body of the catheter has an internal longitudinal structure ofmeshwork braiding, which allows a twisting torque to be applied to theexternal end of the catheter and to ensure that this causes acorresponding rotation of the multilumen needle system fixed onto theterminal end of said catheter.
 27. Catheter system according to claim,25 in which the body of the catheter is provided with a secondlongitudinal electrical conductor which is electrically insulated fromthe conductor connected to the needle system and designed for connectionof the external end to an external electrical apparatus and forconnection of its terminal end to an electrically conducting ringlocated on the terminal end of the catheter and having the function of areference electrode for all the operations where the needle systemperforms the function of a conductor of electrical impulses. 28.Catheter system according to claim 27, in which the said first andsecond electrical conductors are seated, with suitable mutualinsulation, in at least one longitudinal secondary lumen in the body ofthe catheter.
 29. Catheter system according to claim 28, in which anyone of the said electrical conductors may be constituted by the saidtwisting braiding if made of electrically conducting material. 30.Catheter system according to claim 25, in which the external electricalapparatus comprises a source of electric energy and electrical impulses.31. Catheter system according to claim 25, in which the externalelectrical apparatus comprises an apparatus for monitoringelectro-physiological signals.
 32. Catheter system according to claim25, in which the external electrical apparatus comprises an apparatusfor measuring the electrical impedance.
 33. Catheter system according toclaim 1, in which the body of the catheter comprises at least onefilament-like, longitudinally extending, flexible conductor ofultrasound energy which is acoustically coupled to the needle system anddesigned for connection at its external end to an external apparatussupplying ultrasounds.
 34. Catheter system according to claim 1, inwhich the body of the catheter comprises on its terminal end, at thebase of the needle system, a stopping device of the retractable type,with an external activating and deactivating control device, forlimiting the penetration of said needle system into the myocardium. 35.Catheter system according to claim 34, in which the stopping systemcomprises a torus-shaped balloon which is made of flexible andimpermeable material and which, via a connection duct of its internalchamber, is connected to the terminal end of a secondary longitudinallumen in the body of the catheter, the external end of which is designedfor connection to an external system for supplying and drawing fluidinto and from said balloon, respectively so as to fill it and activateit for the end-of-travel function which it must perform, or so as toneutralize it and ensure that it remains in the retracted condition,which is useful during insertion and extraction of the catheter. 36.Catheter system according to claim 35, in which the main lumina in thebody of the catheter are intended to convey the tracer fluid, have theform of a circle segment and are arranged opposite each other inspecular fashion, these lumina having, arranged between them in asymmetrical manner, a first axial secondary lumen for receiving thespindle guiding the catheter during use and there being provided,laterally with respect to this lumen, on the one hand a second secondarylumen for conveying the fluid filling and emptying the end-of-travelballoon (13) and, on the other hand, a third secondary lumen forreceiving the electrical conductors, the ends of which are connected tothe needle system and to the annular reference electrode.
 37. Cathetersystem according to claim 36, in which the lumina of the catheter,except for the first axial lumen, are closed at the external front endand the front section of the said catheter having, mounted on it withoutthe possibility of axial displacement, a rotating distributor or headerprovided around the said catheter with annular chambers which areisolated from each other and with respect to the exterior by annularsealing gaskets and into which chambers there lead, via respectiveradial holes, the two main lumina which are connected to the baseconnecting sections of the needle system and the secondary lumen leadingto the end-of-travel balloon, these chambers being provided withrespective hollow connectors for connection to flexible pipes and tosyringes containing respectively the fluid for filling and emptying saidballoon, the tracer fluid and the therapeutic fluid.
 38. Catheter systemaccording to claim 37, in which the distributor or header is made ofelectrically insulating material and is provided with electricalconductors having brushes which allow an external electrical apparatusto be connected to the electrical conductors which are connected to theneedle system and to the annular reference electrode, the said brushesmaking contact with electrically conducting rings which are fixed ontothe body of the catheter, arranged at a suitable distance from eachother and insulated and fixed to the terminals of the said electricalconductors which emerge from the associated guide lumen through lateralholes.
 39. Catheter system according to claim 5, characterized in that,an ultrasound generator is mounted on the terminal end of the catheter,said ultrasound generator being integral with the base of one or boththe needles of the needle system and connected to an electrical circuitwhich passes through a secondary lumen of the catheter for connection toexternal power supply systems.
 40. Catheter system according to claim 1,in which the body of the catheter has, an external diameter of about 7French, that is about 2.1 mm.
 41. Catheter system according to claim 1,in which the diameter of the helix of the needle system with at leastone helical needle is about 2 mm.
 42. Catheter system according to claim6, in which the length of the projecting section of the longer needle ofthe needle system does not exceed, 5 mm, while the length of theprojecting section of the shorter needle is about 2.5 mm.
 43. Cathetersystem according to claim 5, in which the external diameter of each ofthe needles which form the needle system is about 0.30 mm.